Various imaging systems have been proposed that photographically capture images of a person's face for analysis of the health and aesthetic appearance of the skin. Different images, captured at different times or under different lighting conditions can be used and/or compared to one another to gain insight into the condition of the skin and its response to treatment. This was typically done by human operators inspecting the photographs to identify certain visual indicators of skin condition and to ascertain changes between photographs. When the skin is photographed under an illuminating light, such as a flash or strobe light, the light intensity and wavelength of the light can vary from one photograph to another. Environmental lighting conditions can also lead to variations in illuminating light. Variations in illuminating light can result in variations in the digital images captured which are not attributable to skin condition changes, thereby lessening the probative value of digital imaging analysis.